WO2009013100A2

WO2009013100A2 - Method of combating pollen beetles

Info

Publication number: WO2009013100A2
Application number: PCT/EP2008/058557
Authority: WO
Inventors: Martin Heger; Herve R. Vantieghem
Original assignee: Basf Se
Priority date: 2007-07-20
Filing date: 2008-07-03
Publication date: 2009-01-29
Also published as: EA201000125A1; WO2009013100A3; EP2178368A2

Abstract

This invention relates to a method of combating insect pests of Meligethes spp. (also commonly referred to as pollen beetles) comprising contacting the pests or their food supply, habitat, breeding grounds or their locus with pesticidally effective amounts of N-2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-dicarboximide and at least one pyrethroid.

Description

Method of combating pollen beetles

The present invention relates to a method of combating insect pests of Meligethes spp. (also commonly referred to as "pollen beetles").

Pollen beetles (Meligethes spp.) are small (up to 2 mm long), oval and shiny black. There are several species, the most common being those that breed in brassica seed crops and related plants. They feed pollen and are found on flowers and flower buds from spring to late summer.

Meligethes aeneus is the commonest species breeding on oilseed rape and other yellow Brassicas, though it is also found feeding widely on other flowers. In the spring, adult pollen beetles fly to winter oilseed rape crops. They initially colonise the field margins before venturing further into the crop. The adult beetles feed on pollen. This means they are of no threat to crops in flower, but at green and yellow bud growth stages, they can damage the flowers. Meligethes aeneus is considered to be a pest with a high likelihood of developing insecticide resistance. The cases of observed pollen beetle resistance to pyrethroids are steadily increasing.

Insecticide resistance can arise in several different ways, e.g. through behavioral avoidance, reduced uptake, increased detoxification of the insecticide, and target-site insensitivity. These resistance mechanisms may exist individually in an insect, but are often found in combination (commonly referred to as "multifactorial resistance").

The two major forms of biochemical resistance are target-site resistance, which occurs when the insecticide no longer binds to its target, and detoxification enzyme-based resistance, which occurs when enhanced levels or modified activities of esterases, oxidases, or glutathione S-transferases (GST) prevent the insecticide from reaching its site of action. The enzymes responsible for detoxification of pesticides in many insects are transcribed by members of large multigene families of esterases, oxidases, and GST. Perhaps the most common resistance mechanisms in insects are modified levels or activities of esterase detoxification enzymes that metabolize (hydrolyze ester linkages of) a wide range of insecticides, e.g. pyrethroids.

Conventional strategies for resistance management include the growing of different varieties of the crop, the growing of different crops or the usage of insecticides with a new or different mode of action. Also, the use of certain synergists has been considered in the resistance management of certain insects. Synergists are compounds which, whilst lacking pesticidal properties of their own, enhance the pesticidal properties of other active ingredients.

For example, piperonyl butoxide and N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3- dicarboximide (other name: N-octylbicycloheptenedicarboximide, also widely known as "MGK-264"), both noted as compounds in The Pesticide Manual, 13^th Edition, British Crop Protection Council (2003), are known for their utilization as synergists.

Yerington, A. P. discloses studies on the evaluation of pyrethrins thermal aerosols for the control of vinegar flies and driedfruit beetles in wine cellars by using pyrethrin and a combination of piperonyl butoxide and MGK 264 as synergist (see Journal of Economic Entomology, Vol. 64, No. 4, page 986).

Smith, D. B. discloses studies on the evaluation of permethrin and cypermethrin with the synergist piperonyl butoxide or MGK 264 for control of Colorado patato beetle (Leptinotarsa decemlineata) in potatoes (see Pesticide Research Report, 1983 Meet., pages 122-123).

Ballanger, Y. mentions that the combined use of piperonyl butoxide and pyrethroids against Meligethes species gave promising results on mustard crops (see Oleoscope, No. 70, May 2003, pp. 29-31).

However, there remains a constant need for methods of controlling pollen beetles, in particular pyrethroid-resistant pollen beetles.

Accordingly, it is an object of the present invention to provide a method for the control of pollen beetles. It is another object of this invention to provide a method for the management of the pyrethroid resistance in pollen beetles.

We have found that these objects are in part or in whole achieved by the method according to the invention wherein the insect pests of Meligethes spp. or their food supply, habitat, breeding grounds or their locus are contacted with pesticidally effective amounts of N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and at least one pyrethroid.

Preferably, the insect pests of Meligethes spp. are selected from Meligethes denticulatus, Meligethes solidus, Meligethes fulvipes, Meligethes humerosus, Meligethes subaeneus, Meligethes atratus, Meligethes flavimanus, Meligethes subrugosus, Meligethes corvinus, Meligethes bidens, Meligethes sulcatus, Meligethes atramentarius, Meligethes serrines, Meligethes ochropus, Meligethes difficilis, Meligethes fulvipes, Meligethes humerosus, Meligethes anthracinus, Meligethes coeruleovirens, Meligethes aeneus, Meligethes gracilis, Meligethes czwlinai, Meligethes viridescens, Meligethes lepidii, Meligethes discoideus, Meligethes frivaldszkyi, Meligethes rotundicollis and Meligethes brisouti.

More preferably, the insect pest is Meligethes aeneus.

The term "plant" includes any plant species to which N-(2-ethylhexyl)bicyclo[2.2.1]hept- 5-ene-2,3-dicarboximide and the pyrethroid can be administered, in particular crop plants such as, for example, corn, potato, oilseed rape, mustard, alfalfa, sunflower, cotton, celery, soybean, tobacco, legumes, cereals, and sugarbeet.

The inventive method is especially useful for the control of Meligethes spp. (in particular Meligethes aeneus) in crops of Brassica spp. (in particular oilseed rape crops). It should be understood that the oilseed rape crops may be of either the summer or winter types.

Moreover, the inventive method is especially useful for controlling insect pest of Meligethes spp. exhibiting resistance (in particular metabolic-based resistance and more specifically esterase-based metabolic resistance) to pyrethroids.

Preferably, the pyrethroid is selected from allethrin, bifenthrin, cyfluthrin, cyhalothrin, cyphenothrin, cypermethrin, alpha-cypermethrin, beta-cypermethrin, zeta-cypermethrin, deltamethrin, empenthrin, esfenvalerate, etofenprox, fenpropathrin, fenvalerate, imiprothrin, lambda-cyhalothrin, permethrin, prallethrin, pyrethrin I and II, resmethrin, silafluofen, tau-fluvalinate, tefluthrin, tetramethrin, tralomethrin, transfluthrin, profluthrin and dimefluthrin.

More preferably, the pyrethroid is selected from bifenthrin, alpha-cypermethrin, deltamethrin, esfenvalerate, etofenprox, lambda-cyhalothrin, pyrethrin I and II, tau- fluvalinate and tefluthrin.

Particularly preferred are pyrethroids selected from bifenthrin, alpha-cypermethrin, etofenprox, lambda-cyhalothrin, pyrethrin I and II, and tau-fluvalinate.

In an even more preferred embodiment, the pyrethroid is selected from alpha- cypermethrin or lambda-cyhalothrin.

Most preferably, the pyrethroid is alpha-cypermethrin.

In yet another preferred embodiment, the pyrethroid is lambda-cyhalothrin. More preferably, a composition comprising N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene- 2,3-dicarboximide and a pyrethroid or a mixture of pyrethroids (in particular selected from the aforementioned pyrethroids) is used in the inventive method. It is particularly preferred to use a composition comprising N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene- 2,3-dicarboximide and alpha-cypermethrin or a composition comprising N-(2- ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and lambda-cyhalothrin.

The pyrethroids as mentioned hereinabove are all commercially available compounds which may be found in The Pesticide Manual, 13^th Edition, British Crop Protection Council (2003) among other publications.

For their use according to the present invention, N-(2-ethylhexyl)bicyclo[2.2.1]hept-5- ene-2,3-dicarboximide and the pyrethroid can be converted into the customary formulations, for example solutions, emulsions, suspensions, dusts, powders, pastes and granules. The use form depends on the particular intended purpose; in each case, it should ensure a fine and even distribution of the compounds according to the invention. The terms "active compound(s)", "active ingredient(s)" or "active substance(s)" as used hereinbelow should be understood to refer to both N-(2- ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid, although N- (2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide does not exhibit pesticidal activity.

The formulations are prepared in a known manner (see e.g. for review US 3,060,084, EP-A 707 445 (for liquid concentrates), Browning, "Agglomeration", Chemical Engineering, Dec. 4, 1967, 147-48, Perry' s Chemical Engineer' s Handbook, 4th Ed., McGraw-Hill, New York, 1963, pages 8-57 and et seq. WO 91/13546, US 4,172,714, US 4,144,050, US 3,920,442, US 5,180,587, US 5,232,701 , US 5,208,030, GB 2,095,558, US 3,299,566, Klingman, Weed Control as a Science, John Wiley and Sons, Inc., New York, 1961 , Hance et al., Weed Control Handbook, 8th Ed., Blackwell Scientific Publications, Oxford, 1989 and Mollet, H., Grubemann, A., Formulation technology, Wiley VCH Verlag GmbH, Weinheim (Germany), 2001 , 2. D. A. Knowles, Chemistry and Technology of Agrochemical Formulations, Kluwer Academic Publishers, Dordrecht, 1998 (ISBN 0-7514-0443-8), for example by extending the active compound with auxiliaries suitable for the formulation of agrochemicals, such as solvents and/or carriers, if desired surfactants (e.g. adjuvants, emulsifiers, dispersing agents), preservatives, antifoaming agents, anti-freezing agents.

Examples of suitable solvents are water, aromatic solvents (for example Solvesso products, xylene), paraffins (for example mineral oil fractions), alcohols (for example methanol, butanol, pentanol, benzyl alcohol), ketones (for example cyclohexanone, gamma-butyrolactone), pyrrolidones (NMP, NOP), dialkylsulfoxides (for example dimethylsulfoxide), acetates (glycol diacetate), glycols, fatty acid dimethylamides, fatty acids and fatty acid esters. In principle, solvent mixtures may also be used.

Suitable surfactants used are alkali metal, alkaline earth metal and ammonium salts of lignosulfonic acid, naphthalenesulfonic acid, phenolsulfonic acid, dibutylnaphthalenesulfonic acid, alkylarylsulfonates, alkyl sulfates, alkylsulfonates, fatty alcohol sulfates, fatty acids and sulfated fatty alcohol glycol ethers, furthermore condensates of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensates of naphthalene or of naphthalenesulfonic acid with phenol and formaldehyde, polyoxyethylene octylphenol ether, ethoxylated isooctylphenol, octylphenol, nonylphenol, alkylphenol polyglycol ethers, tributylphenyl polyglycol ether, tristearyl phenyl polyglycol ether, alkylaryl polyether alcohols, alcohol and fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters, lignosulfite waste liquors and methylcellulose.

Substances which are suitable for the preparation of directly sprayable solutions, emulsions, pastes or oil dispersions are mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, furthermore coal tar oils and oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons, for example toluene, xylene, paraffin, tetrahydronaphthalene, alkylated naphthalenes or their derivatives, methanol, ethanol, propanol, butanol, cyclohexanol, cyclohexanone, isophorone, highly polar solvents, for example dimethyl sulfoxide, N-methylpyrrolidone or water.

Also anti-freezing agents such as glycerin, ethylene glycol, propylene glycol and bactericides such as can be added to the formulation.

Suitable antifoaming agents are for example antifoaming agents based on silicon or magnesium stearate.

Suitable preservatives are for example dichlorophen and enzylalkoholhemiformal.

Powders, materials for spreading and dustable products can be prepared by mixing or concomitantly grinding the active substances with a solid carrier.

Granules, for example coated granules, impregnated granules and homogeneous granules, can be prepared by binding the active compounds to solid carriers.

Examples of solid carriers are mineral earths such as silica gels, silicates, talc, kaolin, attaclay, limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground synthetic materials, fertilizers, such as, for example, ammonium sulfate, ammonium phosphate, ammonium nitrate, ureas, and products of vegetable origin, such as cereal meal, tree bark meal, wood meal and nutshell meal, cellulose powders and other solid carriers.

In general, the formulations comprise from 0.01 to 95% by weight, preferably from 0.1 to 90% by weight, of the active compounds. In this case, the active compounds are employed in a purity of from 90% to 100% by weight, preferably 95% to 100% by weight (according to NMR spectrum).

N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid can be used as such, in the form of their formulations or the use forms prepared therefrom, for example in the form of directly sprayable solutions, powders, suspensions or dispersions, emulsions, oil dispersions, pastes, dustable products, materials for spreading, or granules, by means of spraying, atomizing, dusting, spreading or pouring. The use forms depend entirely on the intended purposes; it is intended to ensure in each case the finest possible distribution of the active compounds according to the invention.

Aqueous use forms can be prepared from emulsion concentrates, pastes or wettable powders (sprayable powders, oil dispersions) by adding water. To prepare emulsions, pastes or oil dispersions, the substances, as such or dissolved in an oil or solvent, can be homogenized in water by means of a wetter, tackifier, dispersant or emulsifier. Alternatively, it is possible to prepare concentrates composed of active substance, wetter, tackifier, dispersant or emulsifier and, if appropriate, solvent or oil, and such concentrates are suitable for dilution with water.

The active compound concentrations in the ready-to-use preparations can be varied within relatively wide ranges. In general, they are from 0.0001 to 10%, preferably from 0.01 to 1 % per weight.

The active compound(s) may also be used successfully in the ultra-low-volume process (ULV), it being possible to apply formulations comprising over 95% by weight of active compound, or even to apply the active compound without additives.

The following are examples of formulations: 1. Products for dilution with water for foliar applications.

A) Water-soluble concentrates (SL)

10 parts by weight of the active compound(s) are dissolved in 90 parts by weight of water or a water-soluble solvent. As an alternative, wetters or other auxiliaries are added. The active compound(s) dissolves upon dilution with water, whereby a formulation with 10 % (w/w) of active compound(s) is obtained.

B) Dispersible concentrates (DC) 20 parts by weight of the active compound(s) are dissolved in 70 parts by weight of cyclohexanone with addition of 10 parts by weight of a dispersant, for example polyvinylpyrrolidone. Dilution with water gives a dispersion, whereby a formulation with 20% (w/w) of active compound(s) is obtained.

C) Emulsifiable concentrates (EC)

15 parts by weight of the active compound(s) are dissolved in 7 parts by weight of xylene with addition of calcium dodecylbenzenesulfonate and castor oil ethoxylate (in each case 5 parts by weight). Dilution with water gives an emulsion, whereby a formulation with 15% (w/w) of active compound(s) is obtained.

D) Emulsions (EW, EO)

25 parts by weight of the active compound(s) are dissolved in 35 parts by weight of xylene with addition of calcium dodecylbenzenesulfonate and castor oil ethoxylate (in each case 5 parts by weight). This mixture is introduced into 30 parts by weight of water by means of an emulsifier machine (e.g. Ultraturrax) and made into a homogeneous emulsion. Dilution with water gives an emulsion, whereby a formulation with 25% (w/w) of active compound(s) is obtained.

E) Suspensions (SC, OD) In an agitated ball mill, 20 parts by weight of the active compound(s) are comminuted with addition of 10 parts by weight of dispersants, wetters and 70 parts by weight of water or of an organic solvent to give a fine active compound(s) suspension. Dilution with water gives a stable suspension of the active compound(s), whereby a formulation with 20% (w/w) of active compound(s) is obtained.

F) Water-dispersible granules and water-soluble granules (WG)

50 parts by weight of the active compound(s) are ground finely with addition of 50 parts by weight of dispersants and wetters and made as water-dispersible or water-soluble granules by means of technical appliances (for example extrusion, spray tower, fluidized bed). Dilution with water gives a stable dispersion or solution of the active compound(s), whereby a formulation with 50% (w/w) of active compound(s) is obtained.

G) Water-dispersible powders and water-soluble powders (WP, SP) 75 parts by weight of the active compound(s) are ground in a rotor-stator mill with addition of 25 parts by weight of dispersants, wetters and silica gel. Dilution with water gives a stable dispersion or solution of the active compound(s), whereby a formulation with 75% (w/w) of active compound(s) is obtained.

2. Products to be applied undiluted for foliar applications.

I) Dustable powders (DP)

5 parts by weight of the active compound(s) are ground finely and mixed intimately with 95 parts by weight of finely divided kaolin. This gives a dustable product having 5% (w/w) of active compound(s)

J) Granules (GR, FG, GG, MG)

0.5 part by weight of the active compound(s) is ground finely and associated with 95.5 parts by weightof carriers, whereby a formulation with 0.5% (w/w) of active compound(s) is obtained. Current methods are extrusion, spray-drying or the fluidized bed. This gives granules to be applied undiluted for foliar use.

K) ULV solutions (UL)

10 parts by weight of the active compound(s) are dissolved in 90 parts by weight of an organic solvent, for example xylene. This gives a product having 10% (w/w) of active compound(s), which is applied undiluted for foliar use.

Compositions of this invention may also contain other active ingredients, for example other oils, wetters, adjuvants, herbicides, fungicides, insecticides, herbicides, fertilizers such as ammonium nitrate, boron, molybdenum, sulfur, urea, potash, and superphosphate, phytotoxicants and plant growth regulators, safeners and nematicides. These additional ingredients may be used sequentially or in combination with the above-described compositions, if appropriate also added only immediately prior to use (tank mix). For example, the plant(s) may be sprayed with a composition of this invention either before or after being treated with other active ingredients. Any of the aforementioned additional ingredients can be admixed with the agents according to the invention in a weight ratio of 1 :100 to 100:1.

The pests as defined hereinabove may be controlled by contacting the pest, its food supply, habitat, breeding ground or its locus with pesticidally effective amounts of N-(2- ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid.

"Locus" means a habitat, breeding ground, plant, seed, soil, area, material or environment in which the pest is growing or may grow. The pests may also be controlled by contacting the plant - typically to the foliage, stem or roots of the - with pesticidally effective amounts of N-(2- ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid.

In general, "pesticidally effective amount" means the amount of active ingredient needed to achieve an observable effect on growth, including the effects of necrosis, death, retardation, prevention, and removal, destruction, or otherwise diminishing the occurrence and activity of the pests as defined hereinabove. The pesticidally effective amount can vary for the various compounds/compositions used in the invention. A pesticidally effective amount of the compositions will also vary according to the prevailing conditions such as desired pesticidal effect and duration, weather, target species, locus, mode of application, and the like.

N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid can be applied simultaneously (together or separately) or subsequently, the sequence, in the case of separate application, generally not having any effect on the result of the control measures. It is preferred, however, that N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3- dicarboximide is applied prior to the application of the pyrethroid.

The term "applied simultaneously" should also be understood to mean that N-(2- ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid are applied twice or more than twice (each time together or separately) to e.g. the plant and/or the pest. For example, two applications of N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3- dicarboximide and the pyrethroid can be carried out shortly after each other (e.g. within 3 to 14 days), with N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid being preferably applied together in each application.

In another embodiment, N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide is applied in a non-fast released form. For this purpose, any non-immediate release formulation known in the art, such as sustained, controlled or slow release formulations may be suitable. Preferably, the non-fast release formulation is one that ensures that an effective amount of N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide is released or comes into contact with the plant and/or the pest over a prolonged period of time while the N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide is applied simultaneously to the plant and/or the pest. Such formulations include, for example, N- (2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide encapsulated in a degradable capsule and preferably comprise micro-encapsulation formulations comprising N-(2- ethylhexyObicyclop^.ilhept-δ-ene^^-dicarboximide. In another embodiment, N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and/or the pyrethroid is used in combination with at least one adjuvant that improves its adherence to the plant or the pest.

Examples of adjuvants suitable for this purpose include solvents, wetting agents, sticking agents, spreaders, and penetrating agents.

N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid are generally applied in a weight ratio of from 0.0001 to 10000, preferably from 0.02 to 4000, more preferably from 0.1 to 100, still more preferably from 1 to 100, yet still more preferably from 10 to 100, even more preferably from 10 to 50 and in particular from 20 to 50.

N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid are effective against the pests as defined hereinabove through both contact (via soil or plant parts) and ingestion (plant part) or by direct contact with the insect.

For use in treating crop plants, the rate of application per treatment of N-(2-ethylhexyl)- bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide may be in the range of 1 to 2000 g per hectare (g/ha), preferably from 25 to 1000 g/ha, more preferably from 50 to 500 g/ha, still more preferably from 100 to 500 g/ha and in particular from 100 to 400 g/ha. The rate of application per treatment of the pyrethroid may be in the range of 0.1 to 300 g/ha, preferably from 0.5 to 100 g/ha, more preferably from 1 to 60 g/ha and in particular from 1 to 40 g/ha. Such treatments could be up to 5 and preferably up to 3 times per season in the related crop.

Combinations of specific or preferred embodiments with other specific or preferred embodiments are within the scope of the present invention.

The present invention will be illustrated by the following Examples.

Example

Experiments were carried out in the lab according the GEP settings for indoor testing in using the adult vial test. Two replicates were taken for each treatment. The pollen beetles were taken from commercial oil seed rape fields and were previously confirmed to be resistant against pyrethroids. Small glass tubes (or glass vials) were filled with 1 ml solution of the active ingredient(s) (alpha-cypermethrin alone, MGK 264 alone or combinations of alpha-cypermethrin with MGK 264) in acetone. The solution of the active ingredient in acetone was then equally distributed on the glass wall of the glass tubes by means of a rollmixer. Acetone was then allowed to evaporate completely by opening the glass tubes. After evaporation of the acetone, the glass tubes were closed and stored in a dark and cool (approx. 7°C) location. After bringing the glass tubes back to room temperature, 10 living adult pollen beetles were put in a glass tube which was then closed and stored horizontally during the incubation time. The assessment was made respectively 1 hour later. For each glass tube, the number of beetles that were not able any more to walk on the glass wall of an individual glass tube was counted and noted as "dead". In Table 1 below, the results of the counted "dead" pollen beetles after 1 hour are expressed as a percentage on the total number of beetles initially put in the respective glass tube (hereinafter referred to as "mortality").

Table 1

The results depicted in Table 1 show that alpha-cypermethrin at a rate between 0.1 ppm and 3 ppm had no or only a poor effect on pyrethroid-resistant pollen beetles but when mixed with 300 ppm MGK 264 the mortality was significantly increased from the rate of 0.3 ppm alpha-cypermethrin onwards. The tests performed generally indicate that the combined application of MGK 264 and alpha-cypermethrin as the pyrethroid provided significantly better control of pyrethroid-resistant pollen beetles than using the pyrethroid alpha-cypermethrin alone.

Claims

Claims:

1. A method of combating insect pests of Meligethes spp. comprising contacting the pests or their food supply, habitat, breeding grounds or their locus with pesticidally effective amounts of N-(2-ethylhexyl)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and at least one pyrethroid.

2. The method according to claim 1 wherein the pyrethroid is selected from bifenthrin, alpha-cypermethrin, deltamethrin, esfenvalerate, etofenprox, lambda- cyhalothrin, pyrethrin I and II, tau-fluvalinate and tefluthrin.

3. The method according to claim 1 or 2 wherein the pyrethroid is alpha- cypermethrin.

4. The method according to any one of claims 1 to 3 wherein the pest exhibits resistance to the pyrethroid.

5. The method according to claim 4 wherein the resistance is a metabolic-based resistance.

6. The method according to any one of claims 1 to 5 wherein the pest is selected from Meligethes denticulatus, Meligethes solidus, Meligethes fulvipes, Meligethes humerosus, Meligethes subaeneus, Meligethes atratus, Meligethes flavimanus, Meligethes subrugosus, Meligethes corvinus, Meligethes bidens, Meligethes sulcatus, Meligethes atramentarius, Meligethes serrines, Meligethes ochropus,

Meligethes difficilis, Meligethes fulvipes, Meligethes humerosus, Meligethes anthracinus, Meligethes coeruleovirens, Meligethes aeneus, Meligethes gracilis, Meligethes czwlinai, Meligethes viridescens, Meligethes lepidii, Meligethes discoideus, Meligethes frivaldszkyi, Meligethes rotundicollis and Meligethes brisouti.

7. The method according to claim 6 wherein the pest is Meligethes aeneus.

8. The method according to any one of claims 1 to 7 wherein the plant is selected from Brassica spp.

9. The method according to claim 8 wherein the plant is oilseed rape.

10. The method to any one of claims 1 to 9 wherein N-(2-ethylhexyl)- bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid are applied simultaneously (together or separately) or subsequently.

1 1. The method according to any one of claims 1 to 10 wherein N-(2-ethylhexyl)- bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide is applied prior to the application of the pyrethroid.

12. The method according to any one of claims 1 to 11 wherein N-(2-ethylhexyl)- bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and/ or the pyrethroid is applied in combination with at least one adjuvant that improves its adherence to the plant or the pest.

13. The method according to any one of claims 1 to 12 wherein N-(2-ethylhexyl)- bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide and the pyrethroid are applied in a weight ratio of from 1 to 100.

14. The method according to any one of claims 1 to 13 wherein N-(2-ethylhexyl)- bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide is applied in an amount of from 50 to 500 g/ha.

15. The method according to any one of claims 1 to 14 wherein the pyrethroid is applied in an amount of from 0.1 to 300 g/ha.